Posted 01.24.2011 at 11:13 am
13 Comments
Wisdom Teeth Are On Their Way Out
It will take us a long time to evolve out of our wisdom teeth.
p_x_g on Flickr
Never. We’re probably stuck with our appendix, pinky toes, tailbone and just about all of our other evolutionary holdovers. Wisdom teeth may eventually go, but major changes like losing an appendage (teeth included) take millions and millions of years — who knows if humans will even be around that long. What’s more, most of our seemingly useless vestiges are actually helpful.
The coccyx, or tailbone, “is an attachment point of a number of muscles at the pelvis. We need it for upright locomotion. It would be catastrophic if it went away,” says Kenneth Saladin, an anatomist and physiologist at Georgia College and State University. The appendix, which helped our distant ancestors digest grass, has slowly evolved to take on a new purpose. Research led by William Parker and R. Randall Bollinger of Duke University has shown that the appendix now serves as a kind of “safe house” for the microbes that aid in digestion. “Each of us has 900 to 1,600 species of bacteria in our gut to make sure we have a healthy immune system,” says Stephen Stearns, an evolutionary-biology professor at Yale University. “If one takes over, or they all get flushed out by a disease, then the appendix works like a holding tank for the good bacteria.” Even the pinky toe helps keep our balance and diffuses impact throughout the foot when we run.
There are only a handful of truly useless parts of our body, but these are hanging on too. As Saladin puts it, “since vestiges like the muscles behind our ears have very little impact on reproductive success, there’s no way to select against them.” In other words, the ability to earwiggle doesn’t interfere with having kids. Wisdom teeth were, like the appendix, good when we were eating lots of plants, but today only about 5 percent of us have jaws large enough for these extra molars. “Wisdom teeth are probably on their way out,” Stearns says, “but it will take a long time.”
The silliest of all vestiges is the male nipple. “Those don’t have a function,” Stearns says, “but they won’t disappear either.” All embryos, male and female, begin developing according to the female body plan. Only around the sixth week of gestation do the genes on males’ Y chromosomes kick in. “The basic developmental plan has the two nipples there, so you can’t get rid of them genetically because that would mess up the breasts of females.” And nobody wants that.
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nobody wants that indeed...
Nobody wants that because babies need them to feed... pervert :-P
i agree with ghost, messed up female breasts would DEFINITELY mess with the reproductive cycle!
Actually, if humans left wisdom teeth to evolution - it could take a long time: More likely - virus engineers will work out a way to insert a knock-out gene to prevent wisdom teeth from forming as wisdom teeth. Afterall, geneticists have worked out how the chicken genome prevents teeth formation. In any case, humans need a smarter location for Blue Tooth transceivers for voice and music communications, and wisdom teeth are taking up prime real estate close to the inner ear. I think lots of people would give up wisdom teeth for surround sound Apple iTeeth.
I have no wisdom teeth. They do not exist in my skull so I will never have to have them removed. I'm not bragging, I'm just saying. I am curious to see if my kids will have them or not.
There would have to be a lot of mating going on for those without wisdom teeth to only reproduce with each other to ensure the offspring don't have the teeth grow. Who knows, in a million years, which really is a damn long time, there might be a big portion of the population with no wisdom teeth gene.
lucky for me, i have room for mine so im really good at chewing.
"In other words, the ability to earwiggle doesn’t interfere with having kids."
Unless you're a guy, who thinks earwiggling impresses girls.
I was thrilled when my dentist told me I never developed wisdom teeth! Different sources write 20-35% of people never get them- I'm glad to be one of the lucky ones.
Stearns needs to get out of the lab a bit more if he thinks the male nipple has no function. :-P
Regarding wisdom teeth, my upper two are impacted and cause no trouble so I like to think they are spares should I lose one of the visible ones.
As for the muscles behind the ear ... I would think they help in making expressions.
I'm one of the lucky 5% who has a jaw large enough to handle wisdom teeth without any problems :D
(see my large-jawed grin?)
@Far Out Man
I totally agree about the muscles behind the ear. I didnt even realize it, but my Ex-Girlfriend told me that whenever I felt guilty (ergo lying to her XP) that I pull my ears back.
I'm in the 5% with jaws big enough for wisdom teeth. I can't even remember what it was like without them
I don't think "never" is "ever" the right answer when speculating. There is evidence that humans can measurably evolve (linguistically and sociologically) within the short span of one human lifetime.
With specific regard to the fifth toe, I have been a practicing podiatrist for 35 years. Early in my practice, perhaps 5% of the feet in all age-groups I X-rayed had two (instead of the common three) bones in the pinky toe. Now, especially amongst those under 30 years of age, the incidence of two-boned pinkies I X-ray is consistently 40-45%.